1. Field of the Invention
The present invention relates to a method for producing a magnetic recording medium and an apparatus for implementing the method.
2. Description of the Related Art
During the production of a magnetic recording medium, the surface of a polymeric film on which a magnetic coating material is to be coated is customarily cleaned prior to coating in order to improve the error ratio of high-density recording in the finished product.
Known examples of a cleaning method for a polymeric film include a method of blowing cleaning air at a high speed onto the surface of the polymeric film while the film is running on a back-up roll in order to separate foreign matter from the surface of the polymeric film and to blow it towards a suction duct located adjacent the surface of film, and a method of supplying a cleaning agent to the surface of the polymeric film and removing both the foreign matter and the cleaning agent with one or more doctor blades.
However, the method of blowing cleaning air onto the surface of the polymeric film cannot always successfully remove foreign matter strongly adhering to the surface of the film. Also, the method of removing foreign matter with doctor blades has a tendency to scratch the surface of the film, thus making impossible consistently to obtain a good quality coated film.
An object of this invention is thus to reliably remove foreign matter adhering to the surface of a polymeric film without damaging the surface of the polymeric film.
In accordance with the above and other objects, a first aspect of the present invention relates to a method for producing a magnetic recording medium having a magnetic material coated on a surface of a polymeric film comprising, in the running direction of the polymeric film, the steps of:
pressing a cleaning tape made of one of a non-woven fabric and a fabric impregnated with a cleaning agent against the surface of said polymeric film onto which said coating material is coated in order to wipe off foreign matter adhering to said surface of the polymeric film;
drying the surface of the wiped polymeric film; and just after the drying step,
coating a magnetic coating material onto a surface of a polymeric film while said polymeric film is running.
In the present invention xe2x80x9cthe running direction of the polymeric filmxe2x80x9d means from upstream to downstream of the running polymeric film. In the present invention a magnetic material may be coated as an upper layer together with a magnetic or non-magnetic intermediate layer as a lower layer simultaneously onto a surface of a polymeric film.
A second aspect of the present invention relates to an apparatus for producing a magnetic recording medium having a magnetic material coated on a surface of a polymeric film comprising, in the running direction of the polymeric film:
a wiping apparatus for pressing a cleaning tape made of one of a non-woven fabric and a fabric impregnated with a cleaning agent against said surface of said polymeric film for wiping off foreign matter adhering to said surface of said polymeric film;
a drying apparatus for drying said surface of said polymeric film; and
a coating apparatus for applying a coating of a magnetic material to the surface of the running polymeric film,
wherein the drying apparatus is closely positioned to the wiping apparatus, and the coating apparatus is closely positioned to the drying apparatus.